How do I define a network policy YML file so it only allows traffic to and from a hostname like console.cloud.ibm.com?
I only can find how to block from certain IP addresses or namespaces.
You can use Network Policies to block the IP address of what resolves to:
$ dig +short console.cloud.ibm.com
23.204.34.209The downside is that the IP might change. Network policies are a layer 3 or IP layer feature so you won't see hostnames there. Some background here
If you want to block on hostname you might consider using a Service Mesh like Istio with Envoy which will allow you to control traffic to a host by using Egress Control.